It is known to use bentonite or bentonite-containing materials as a waterproofing agent in the construction industry. The bentonite clay compositions are known to swell when contacted with water and accordingly are used against exterior structures such as mines, dams, artificial lakes, reservoirs, expansion joints, masonry construction, oil wells, pipes, building foundations, basements and other structures to prevent or minimize the entrance of water therein. The bentonite materials are generally dispersed or suspended in non-aqueous mediums such as crude oil, alcohol, or gelling agents. Highly colloidal clay or other materials which possess the capacity to swell or gelatinize upon contact with water are also known carriers for the bentonite waterproofing material. Ingredients such as further gelling agents, waxes, thickening agents and the like are usually incorporated into the waterproofing composition to enhance its sustaining properties, however the presence of these ingredients also reduces the percent of the effective component bentonite clay in the composition. The bentonite clay used in the prior art has been of both the swelling and non-swelling types depending upon the desired effects. It has been incorporated in solid structures such as barriers formed of concrete, containing structures or grids, sand or gravel, or other solid containers and membranes.
In using waterproofing compositions, it is important to utilize compositions having maximum waterproofing properties. In known compositions, putty-like masses are formed from bentonite having added thereto from 100 to about 150 parts water for each 100 parts bentonite. The resulting pre-swelled materials have already used up part of their water absorbing properties and are thus not mass-effect efficient. About 30% of the bentonite used is rendered relatively ineffective because of the necessary pre-swelling as a result of the partial initial hydration. An embodiment similar to this pre-swelled composition is disclosed in U.S. Pat. No. 2,277,286.
Other compositions utilize bentonite gells containing in addition to the bentonite clay a non-aqueous liquid and a gelling agent. The base of the waterproofing composition is a non-aqueous medium with agar agar. The non-aqueous medium could be oil, glycerine, or an alcohol. The non-aqueous liquid usually could comprise up to 85% by weight of the total composition, and the gelling agent is added in amounts of from 15-60%. The range left for the bentonite clay usually is from about 30% to 70% by weight of the total bentonite composition. This means that from about 30% to 70% of the waterproofing composition is non-waterproofing in nature, because of the necessary addition of materials to maintain the cohesiveness of the material. These materials have been used as waterproofing compositions having the consistency of modeling clay or in the alternative, can be applied over the face or surface of a water permeable support sheet such as corrugated paperboard. In either embodiment, the compositions contain a significant amount of non-functional waterproofing ingredients. Compositions similar to these are disclosed in U.S. Pat. Nos. 4,279,547 and 2,065,512.
The prior art therefore provides waterproofing materials, or paste-like masses, that are water pre-swelled, thus losing effectiveness, and diluted in content in final composition, thus again further losing effectiveness.
Other systems comprise the use of membranes supports or casings to contain the waterproofing compositions. The casing of water permeable material contains the bentonite waterproofing composition and permits water or other liquids to pass therethrough and contact the bentonite. Upon contact, the water activates the water impeding characteristics of the bentonite composition. On the opposite face of the bentonite containing composition is a water impervious membrane designed in a predetermined pattern for retaining the bentonite material in its intended position. The water impervious membrane is necessary to prevent the rupture of the permeable face or sheathing and to prevent loss of the bentonite material before activation.
Various water permeable support sheets have been used such as those disclosed in U.S. Pat. Nos. 4,279,547 and 3,445,322. These water permeable sheets contain the bentonite composition and also permit water to contact this composition to activate its water impeding characteristics. Not only is it relatively expensive to manufacture these waterproofing components, but also the surface contact with the actual waterproofing material is reduced substantially. The prior art sheets or building components usually comprise a waterproofing material sandwiched between a water impervious backing material on one face and a water pervious facing layer on the other face. The building components consist of a plurality of compartments into which the composition is housed, part of the area of the component face consists of the water impervious material and the remainder waterproofing composition. Irrespective of the configuration or design of the component, the waterproofing area that contacts the inner face of the water pervious layer is substantially less than maximum area. This is because the receptacles that contain the waterproofing composition must by necessity take up part of this area. Various configurations are disclosed in U.S. Pat. Nos. 2,277,286; 3,445,322; 3,561,177; and 4,279,547.
A further serious problem in prior art waterproofing structures is that because of the cardboard or paperboard facings, the bentonite is not held firmly in place when in use. The cardboard outer and surface facings contain the bentonite materials in a sandwich-like configuration. The cardboard has an internally corrugated surface into which the bentonite fits and is maintained. However, upon becoming wet, the cardboard looses its holding capacity and the bentonite falls to the bottom of the sandwich-like structure and is thus not effective as a waterproofing agent. Once the bentonite is dislocated from its original position along the entire facing area, the waterproofing properties of the structure are lost.
Further, when paperboard or cardboard are used as facings, the cardboard deteriorates in time and upon becoming wet, causes the bentonite to sag or fall. When this occurs, the waterproofing properties are seriously impaired at the stage where maximum waterproofing is desired, i.e., during water seepage or contact. Also it is not unusual for the cardboard facing to easily puncture and allow the waterproofing material or bentonite to seep out of position. Again, this substantially reduces the total effectiveness of the waterproofing structure.
The prior art, therefore, provides structures and systems for waterproofing components having at least three major drawbacks:
(1) They are often water pre-swelled, thereby losing the pre-swelled portion effectiveness when activated in use by contact with water or liquids; PA0 (2) They are often diluted with substantial amounts of other components such as gelling agents, dispersing agents, non-aqueous liquids, waxes, thickening agents and other relatively non-functional waterproofing ingredients; PA0 (3) They are often used together with structures that have receptacles that impede or minimize the area contact of the waterproofing material with the surface structure to be waterproofed. PA0 (A) a material selected from the group consisting of dialkylphthalate, dialkyloxalate, succrose acetate isobutyrate, glycerine, and mixtures thereof; PA0 (B) a material selected from the group consisting of polyalkylmethacrylate, cellulose acetate, polyvinylalcohol, polyvinylbutyral, and mixtures thereof.